1. Field of the Invention
The present invention relates to an ink jet printer.
2. Description of the Related Art
An ink jet printer replenishes an ink jet head (recording head) with ink by using a high-capacity ink bottle as an ink supply source. Specifically, ink in an ink bottle is supplied to a small-capacity sub tank or an ink reservoir through a flexible tube. The ink in the sub tank or the ink reservoir is supplied to the recording head.
This above-described type of ink jet printer is disclosed in, e.g., Jpn. Pat. Appln. KOKAI Publication No. 2001-260389. The ink jet printer in the above-described publication has a supply pump used to supply the ink in the ink bottle to the sub tank. Further, the ink jet printer has ink sucking means for filling the ink in the recording head.
The ink sucking means is provided in a maintenance area which is a non-recording area. This ink sucking means has a cap which seals a nozzle formed surface of the recording head and a pump which forms a negative pressure in a space in the cap. Furthermore, this ink sucking means can be moved between a cap position and a non-cap position by driving of cap driving means. The cap position is a position at which the ink sucking means is pressed against a nozzle surface of the recording head. The non-cap position is a position at which the ink sucking means is separated from the nozzle surface of the recording head.
In the ink jet printer in the above-described publication, when filling the ink in the recording head, the recording head is moved to a position where the ink sucking means exists. Subsequently, the cap driving means moves the cap of the ink sucking means to the cap position. The cap caps the nozzle surface by this movement. After completion of capping, the ink sucking means drives a suction pump. This suction pump sucks the ink from the sub tank by forming a negative pressure in the cap. By this suction, the ink is filled in the recording head, and air or air bubbles existing in the recording head are discharged from the recording head.
Users of the ink jet printer in recent years very strongly expect an improvement in throughput. Therefore, the number of nozzles per recording head of the ink jet printer tends to be increased. Moreover, in the ink jet printer, there is also used a recording head in which the number of nozzles per unit obtained by forming a unit by connecting a plurality of recording heads is increased.
Such a recording head or recording head unit has a dimension which is large in a nozzle column direction. Therefore, in order to cap the nozzle column, the cap of the ink sucking means must be also increased in size. However, if a dimension of the cap is increased, the press of the cap with respect to the nozzle surface of the recording head is lowered. Therefore, the ink sucking means with the large cap dimension cannot excellently fill the ink in the recording head, and it may not excellently remove air or air bubbles in the recording head.
Additionally, the ink jet printer in the above-described publication requires various kinds of pumps such as a supply pump used to supply the ink or a suction pump used to fill the ink in the recording head. That is, the ink jet printer in the above-described publication has an inconvenience that the number of components is increased.
Further, the various kinds of pumps may possibly generate bubbles such as air bubbles in the ink by a pumping operation. If the bubbles reach the inside of the recording head, they may possibly generate a discharge failure of the ink in the recording head.
In view of the above-described drawbacks, it is an object of the present invention to provide an ink jet printer which can fill ink in an ink supply path and remove air in the ink supply path without comprising ink sucking means for sucking ink from an ink bottle or a sub tank and filling the ink in the ink supply path.
Furthermore, it is another object of the present invention to provide an ink jet printer which can supply ink to a sub tank or an ink head without comprising the supply pump which supplies ink from an ink bottle.